Stack packages including a fan-out sub-package

ABSTRACT

A stack package includes a package substrate and a fan-out sub-package mounted on the package substrate using first and second connection bumps. The fan-out sub-package includes a first semiconductor die and redistributed line (RDL) patterns. Second semiconductor dies are stacked on the package substrate to provide a first step structure, and third semiconductor dies are stacked on the second semiconductor dies to provide a second step structure. The second and third semiconductor dies are connected to the package substrate by bonding wires.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C 119(a) to Korean Application No. 10-2019-0051865, filed on May 2, 2019, which is incorporated herein by references in its entirety.

BACKGROUND 1. Technical Field

Embodiments of the present disclosure relate to package technologies and, more particularly, to stack packages including a fan-out sub-package.

2. Related Art

Recently, high performance semiconductor packages have been proposed to improve operation speed. Each of the high performance semiconductor packages may be fabricated to include a plurality of semiconductor dies which are stacked on a package substrate. A wire bonding technique may be used to electrically connect the plurality of semiconductor dies to the package substrate. As an amount of data processed by an electric system increases, it may be necessary to increase the number of input/output (I/O) terminals of the semiconductor die in order to process the data at a high speed. In such a case, advanced techniques may be required to electrically connect the I/O terminals of the semiconductor die to the package substrate.

SUMMARY

According to an embodiment, a stack package includes a package substrate, a fan-out sub-package mounted on the package substrate using first connection bumps and second connection bumps, second semiconductor dies stacked on the fan-out sub-package, third semiconductor dies stacked on the second semiconductor dies, first bonding wires connected to the second semiconductor dies, and second bonding wires connected to the third semiconductor dies. The package substrate includes first wire bond fingers connected to the first bonding wires, second wire bond fingers connected to the second bonding wires, first bump bond fingers to which the first connection bumps are connected, and second bump bond fingers to which the second connection bumps are connected. The fan-out sub-package includes an encapsulating layer embedding a first semiconductor die, first redistributed line (RDL) patterns extending from a surface of the first semiconductor die and connecting to the first connection bumps disposed on a bottom surface of the encapsulating layer, and second RDL patterns extending from the surface of the first semiconductor die and connecting the first semiconductor die to the second connection bumps disposed on the bottom surface of the encapsulating layer.

According to another embodiment, a stack package includes a package substrate, a fan-out sub-package mounted on the package substrate using first connection bumps and second connection bumps, second semiconductor dies stacked on the fan-out sub-package to provide a step structure, bonding wires connecting the second semiconductor dies to the package substrate, and dummy bumps disposed between the first connection bumps and the second connection bumps to structurally support the fan-out sub-package. The fan-out sub-package includes an encapsulating layer embedding a first semiconductor die, first redistributed line (RDL) patterns extending from a surface of the first semiconductor die and connecting to the first connection bumps disposed on a bottom surface of the encapsulating layer, and second RDL patterns extending from the surface of the first semiconductor die and connecting the first semiconductor die to the second connection bumps disposed on the bottom surface of the encapsulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a stack package according to an embodiment.

FIGS. 2 and 3 are enlarged cross-sectional views illustrating portions of the stack package shown in FIG. 1.

FIG. 4 is a plan view illustrating wire bond fingers, connection bumps, and die pads of the stack package shown in FIG. 1.

FIG. 5 is an enlarged plan view illustrating the die pads shown in FIG. 4.

FIG. 6 is a plan view illustrating the connection bumps and the die pads shown in FIG. 4.

FIG. 7 is an enlarged cross-sectional view illustrating an edge portion of a fan-out sub-package included in a stack package according to an embodiment.

FIG. 8 is a cross-sectional view illustrating a stack package according to another embodiment.

FIG. 9 is a cross-sectional view illustrating a stack package according to yet another embodiment.

FIG. 10 is a block diagram illustrating an electronic system employing a memory card including at least one stack package according to an embodiment.

FIG. 11 is a block diagram illustrating another electronic system including at least one stack package according to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The terms used herein may correspond to words selected in consideration of their functions in the embodiments, and the meanings of the terms may be construed to be different according to ordinary skill in the art to which the embodiments belong. If defined in detail, the terms may be construed according to the definitions. Unless otherwise defined, the terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments belong.

It will be understood that although the terms “first,” “second,” “third,” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish similar elements from one another and are not used to indicate a number or sequence of such elements.

It will also be understood that when an element or layer is referred to as being “on,” “over,” “below,” “under,” or “outside” another element or layer, the element or layer may be in direct contact with the other element or layer, or intervening elements or layers may be present. Other words used to describe the relationship between elements or layers should be interpreted in a like fashion (e.g., “between” versus “directly between” or “adjacent” versus “directly adjacent”).

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” “top,” “bottom,” and the like, may be used to describe an element and/or feature's relationship to another element(s) and/or feature(s) as, for example, illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and/or operation in addition to the orientation depicted in the figures. For example, when the device in the figures is turned over, elements described as below and/or beneath other elements or features would then be oriented above the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

A stack package may correspond to a semiconductor package, and the semiconductor package may include electronic devices such as semiconductor chips or semiconductor dies. The semiconductor chips or the semiconductor dies may be obtained by separating a semiconductor substrate, such as a wafer, into a plurality of pieces using a die sawing process. The semiconductor chips may correspond to memory chips, logic chips, or application specific integrated circuit (ASIC) chips. The memory chips may include dynamic random access memory (DRAM) circuits, static random access memory (SRAM) circuits, NAND-type flash memory circuits, NOR-type flash memory circuits, magnetic random access memory (MRAM) circuits, resistive random access memory (ReRAM) circuits, ferroelectric random access memory (FeRAM) circuits or phase change random access memory (PcRAM) circuits which are integrated on the semiconductor substrate. The semiconductor package may be employed in communication systems such as mobile phones, electronic systems associated with biotechnology or health care, or wearable electronic systems. The semiconductor packages may be applicable to internet of things (IoT).

Same reference numerals refer to same elements throughout the specification. Even though a reference numeral is not mentioned or described with reference to a drawing, the reference numeral may be mentioned or described with reference to another drawing. In addition, even though a reference numeral is not shown in a drawing, it may be mentioned or described with reference to another drawing.

FIG. 1 is a cross-sectional view illustrating a stack package 10 according to an embodiment.

Referring to FIG. 1, the stack package 10 may be configured to include a package substrate 100, a fan-out sub-package 500 embedding a first semiconductor die 200, and a first stack 701 including a plurality of second semiconductor dies 711. A second stack 702 including a plurality of third semiconductor dies 712 may be stacked on the first stack 701 including the plurality of second semiconductor dies 711. The stack package 10 may further include a plurality of first bonding wires 801 and a plurality of second bonding wires 802. The fan-out sub-package 500 may be mounted on the package substrate 100 using a plurality of first connection bumps 601 and a plurality of second connection bumps 602 disposed between the fan-out sub-package 500 and the package substrate 100. The first and second connection bumps 601 and 602 may be spaced apart from the first semiconductor die 200 when viewed from a plan view.

The stack package 10 may further include an outer encapsulating layer 900 that is disposed on the package substrate 100 to cover and protect the fan-out sub-package 500, the first stack 701, and the second stack 702. The outer encapsulating layer 900 may include a package molding material such as an epoxy molding compound (EMC) material.

The package substrate 100 may include an interconnection structure electrically connecting the stack package 10 to an external device. The package substrate 100 may be a printed circuit board (PCB). The package substrate 100 may have a first surface 101 on which the fan-out sub-package 500 is stacked and a second surface 102 which is located on an opposite side from the fan-out sub-package 500. Outer connectors 109 may be disposed on the second surface 102 of the package substrate 100. The outer connectors 109 may include connection members which are capable of being connected to an external device. For example, the outer connectors 109 may include solder balls.

First wire bond fingers 140 and second wire bond fingers 170 may be disposed on the first surface 101 of the package substrate 100. The first wire bond fingers 140 and the second wire bond fingers 170 may be disposed on opposite end portions of the package substrate 100. That is, the first wire bond fingers 140 may be disposed on the first surface 101 of a first end portion of the package substrate 100, and the second wire bond fingers 170 may be disposed on the first surface 101 of a second end portion of the package substrate 100 opposite to the first end portion. The first wire bond fingers 140 may be disposed on the first end portion of the package substrate 100 to be adjacent to a first end portion of the fan-out sub-package 500, and the second wire bond fingers 170 may be disposed on the second end portion of the package substrate 100 to be adjacent to a second end portion of the fan-out sub-package 500. The first wire bond fingers 140 and the second wire bond fingers 170 may be disposed at both sides of a portion of the package substrate 100, which overlaps with the fan-out sub-package 500, respectively. Accordingly, the first wire bond fingers 140 may be separated from the second wire bond fingers 170 by a central region of the package substrate 100 overlapping with the fan-out sub-package 500.

The first bonding wires 801 may be electrically connected to the first wire bond fingers 140, respectively. The second bonding wires 802 may be electrically connected to the second wire bond fingers 170, respectively. The first bonding wires 801 may electrically connect the second semiconductor dies 711 of the first stack 701 to the first wire bond fingers 140. The second bonding wires 802 may electrically connect the third semiconductor dies 712 of the second stack 702 to the second wire bond fingers 170. The first bonding wires 801 may be disposed at a first side of the first stack 701, and the second bonding wires 802 may be disposed at a second side of the first stack 701 opposite to the first bonding wires 801.

The first stack 701 may be configured to include the second semiconductor dies 711 which are stacked. The second semiconductor dies 711 may be sequentially stacked to be laterally offset to provide a first step structure 701S. For example, the second semiconductor dies 711 may be sequentially stacked to be offset in a first offset direction directed from the first wire bond fingers 140 toward the second wire bond fingers 170. The second semiconductor dies 711 may be stacked to reveal their edge portions to which the first bonding wires 801 are connected. The second semiconductor dies 711 may be attached to and stacked on the fan-out sub-package 500 using a first adhesive layer 721.

The second stack 702 may be configured to include the third semiconductor dies 712 which are stacked. The third semiconductor dies 712 may be sequentially stacked to be laterally offset to provide a second step structure 702S. For example, the third semiconductor dies 712 may be sequentially stacked to be offset in a second offset direction directed from the second wire bond fingers 170 toward the first wire bond fingers 140. The second offset direction may be opposite to the first offset direction. The third semiconductor dies 712 may be stacked to reveal their edge portions to which the second bonding wires 802 are connected. The third semiconductor dies 712 may be attached to and stacked on the first stack 701 using a second adhesive layer 722.

The first bonding wires 801 may include first sub-bonding wires 811 electrically connecting the first wire bond fingers 140 of the package substrate 100 to a second bottommost semiconductor die 7118 corresponding to a bottommost die of the first stack 701. The second bottommost semiconductor die 711B may be a semiconductor die which is closest to the package substrate 100 among the second semiconductor dies 711. The first bonding wires 801 may further include second sub-bonding wires 821 electrically connecting the second semiconductor dies 711 to each other. The first sub-bonding wires 811 may be electrically connected to the second sub-bonding wires 821.

The second bonding wires 802 may electrically connect the second bond fingers 170 to the second stack 702 including the third semiconductor dies 712 and may extend to electrically connect the third semiconductor dies 712 to each other.

First bump bond fingers 150 and second bump bond fingers 180 may be disposed on the first surface 101 of the package substrate 100. The first bump bond fingers 150 may be electrically connected to the first wire bond fingers 140. The first bump bond fingers 150 may be electrically connected to the first wire bond fingers 140 through first interconnection lines 160 disposed on the first surface 101 of the package substrate 100. The second bump bond fingers 180 may be electrically connected to the second wire bond fingers 170 through second interconnection lines 190 disposed on the first surface 101 of the package substrate 100.

The first connection bumps 601 may be physically and mechanically bonded to and electrically connected to the first bump bond fingers 150, respectively. The second connection bumps 602 may be physically and mechanically bonded to and electrically connected to the second bump bond fingers 180, respectively. The first and second connection bumps 601 and 602 may be substantially identical or similar connection members. For example, each of the first and second connection bumps 601 and 602 may be configured to include a bump body 611 and a conductive adhesive layer 612. The bump body 611 may be formed to include a metal material such as a copper material, and the conductive adhesive layer 612 may be formed to include a solder layer. The bump bodies 611 of the first and second connection bumps 601 and 602 may be connected to the fan-out sub-package 500, and the conductive adhesive layers 612 of the first and second connection bumps 601 and 602 may be connected to the first and second bump bond fingers 150 and 180.

The fan-out sub-package 500 may be formed to have a fan-out package form embedding the first semiconductor die 200. For example, the fan-out sub-package 500 may be configured to include the first semiconductor die 200, an inner encapsulating layer 300, and first and second redistributed line (RDL) patterns 401 and 402.

The inner encapsulating layer 300 may cover and embed the first semiconductor die 200 to act as a body of the fan-out sub-package 500. The inner encapsulating layer 300 may include a package molding material such as an epoxy molding compound (EMC) material. The inner encapsulating layer 300 may be disposed to reveal a surface 201 of the first semiconductor die 200. First die pads 210 and second die pads 220 may be disposed on the surface 201 of the first semiconductor die 200. The first die pads 210 and the second die pads 220 may be connection terminals which are connected to the first semiconductor die 200.

The first semiconductor die 200 may be disposed on the package substrate 100 such that the surface 201 of the first semiconductor die 200 faces the first surface 101 of the package substrate 100. The first semiconductor die 200 may be disposed in a region between the first wire bond fingers 140 and the second wire bond fingers 170.

The first semiconductor die 200 may be electrically connected to the second semiconductor dies 711 of the first stack 701 and the third semiconductor dies 712 of the second stack 702. The first semiconductor die 200 may be configured to include a controller that controls operations of the second semiconductor dies 711 of the first stack 701 and operations of the third semiconductor dies 712 of the second stack 702. The second semiconductor dies 711 of the first stack 701 and the third semiconductor dies 712 of the second stack 702 may be memory semiconductor dies for storing data. The second semiconductor dies 711 of the first stack 701 and the third semiconductor dies 712 of the second stack 702 may be memory semiconductor dies that supply data to the first semiconductor die 200 and/or store data by a control operation of the first semiconductor die 200. The second semiconductor dies 711 and the third semiconductor dies 712 may be NAN-type flash memory devices.

FIGS. 2 and 3 are enlarged cross-sectional views illustrating portions (including the fan-out sub-package 500) of the stack package 10 shown in FIG. 1.

Referring to FIGS. 1 and 2, the first semiconductor die 200 may be electrically connected to the second semiconductor dies 711 of the first stack 701 through the first RDL patterns 401, the first connection bumps 601, the first bump bond fingers 150, the first interconnection lines 160, the first wire bond fingers 140, and the first bonding wires 801. As such, the first RDL patterns 401, the first connection bumps 601, the first bump bond fingers 150, the first interconnection lines 160, the first wire bond fingers 140, and the first bonding wires 801 may provide a first channel for communication between the first semiconductor die 200 and the second semiconductor dies 711.

Referring to FIGS. 1 and 3, the first semiconductor die 200 may be electrically connected to the third semiconductor dies 712 of the second stack 702 through the second RDL patterns 402, the second connection bumps 602, the second bump bond fingers 180, the second interconnection lines 190, the second wire bond fingers 170, and the second bonding wires 802. As such, the second RDL patterns 402, the second connection bumps 602, the second bump bond fingers 180, the second interconnection lines 190, the second wire bond fingers 170, and the second bonding wires 802 may provide a second channel for communication between the first semiconductor die 200 and the third semiconductor dies 712. The first semiconductor die 200 may communicate with the second and third semiconductor dies 711 and 712 using a plurality of channels (i.e., the first and second channels), thereby improving an operation speed of the stack package 10.

Referring again to FIGS. 1 and 2, the first RDL patterns 401 may electrically connect the first semiconductor die 200 to the first connection bumps 601. The first RDL patterns 401 may extend from the surface 201 of the first semiconductor die 200 onto a bottom surface of the inner encapsulating layer 300. The first RDL patterns 401 may extend from the surface 201 of the first semiconductor die 200 to be connected to the first connection bumps 601 disposed on the bottom surface of the inner encapsulating layer 300. The first

RDL patterns 401 may be formed of a metal layer. The first RDL patterns 401 may include a copper material or an aluminum material. Each of the first RDL patterns 401 may be a conductive pattern including a first portion 411, a first extension portion 412, and a second portion 413. The first portions 411 of the first RDL patterns 401 may be lands to which the first connection bumps 601 are connected. The first portions 411 of the first RDL patterns 401 may be disposed on the bottom surface of the inner encapsulating layer 300 to be laterally spaced apart from the first semiconductor die 200. The second portions 413 of the first RDL patterns 401 may be disposed to vertically overlap with the first die pads 210 of the first semiconductor die 200 and may be electrically connected to the first die pads 210. The first extension portions 412 of the first RDL patterns 401 may be line-shaped patterns electrically connecting the first portions 411 to the second portions 413.

Referring again to FIGS. 1 and 3, the second RDL patterns 402 may extend in an opposite direction to a direction in which the first RDL patterns 401 extend from the surface 201 of the first semiconductor die 200. The second RDL patterns 402 may extend from the surface 201 of the first semiconductor die 200 onto the bottom surface of the inner encapsulating layer 300 and may also extend toward the second connection bumps 602. The second RDL patterns 402 may electrically connect the first semiconductor die 200 to the second connection bumps 602. Each of the second RDL patterns 402 may be a conductive pattern including a third portion 415, a second extension portion 416, and a fourth portion 417. The third portions 415 of the second RDL patterns 402 may be lands to which the second connection bumps 602 are connected. The third portions 415 of the second RDL patterns 402 may be disposed on the bottom surface of the inner encapsulating layer 300 to be laterally spaced apart from the first semiconductor die 200. The fourth portions 417 of the second RDL patterns 402 may be disposed to vertically overlap with the second die pads 220 of the first semiconductor die 200 and may be electrically connected to the second die pads 220. The second extension portions 416 of the second RDL patterns 402 may be line-shaped patterns electrically connecting the third portions 415 to the fourth portions 417.

A dielectric layer 350 may be disposed on the bottom surface of the inner encapsulating layer 300 to cover the first semiconductor die 200 and the first and second RDL patterns 401 and 402. The first and second RDL patterns 401 and 402 may be electrically isolated from each other by the dielectric layer 350. The dielectric layer 350 may include a solder resist layer.

Referring to FIG. 2, first electrical paths P1 may be formed to include the first die pads 210, the first RDL patterns 401, the first connection bumps 601, the first bump bond fingers 150, the first interconnection lines 160, and the first wire bond fingers 140. Referring to FIG. 3, second electrical paths P2 may be formed to include the second die pads 220, the second RDL patterns 402, the second connection bumps 602, the second bump bond fingers 180, the second interconnection lines 190, and the second wire bond fingers 170. One of the first electrical paths P1 may be disposed to have substantially the same length as any one of the second electrical paths P2.

In an embodiment, one of the first RDL patterns 401 may be formed to have substantially the same length as any one of the second RDL patterns 402. In another embodiment, corresponding first 401 and second 402 RDL patterns may be formed to have substantially the same length. The first RDL patterns 401 may have a symmetric layout to the second RDL patterns 402 with respect to the first semiconductor die 200 in a plan view. In such a case, the first die pads 210 of the first semiconductor die 200 may also be symmetric to the second die pads 220 of the first semiconductor die 200 with respect to a straight line passing through a central point of the first semiconductor die 200 when viewed in a plan view. The first die pads 210 of the first semiconductor die 200 may also be point symmetric to the second die pads 220 of the first semiconductor die 200 with respect to a central point of the first semiconductor die 200 when viewed from a plan view.

The first bump bond fingers 150, the first interconnection lines 160, and the first wire bond fingers 140 may have substantially the same lengths and shapes as the second bump bond fingers 180, the second interconnection lines 190, and the second wire bond fingers 170, respectively. The first bump bond fingers 150, the first interconnection lines 160, and the first wire bond fingers 140 may be disposed to be symmetric to respective ones of the second bump bond fingers 180, the second interconnection lines 190, and the second wire bond fingers 170 with respect to the first semiconductor die 200 when viewed in a plan view.

As a result of the layout described above, it may be possible to effectively reduce a difference in length between a path connecting the first semiconductor die 200 to the second semiconductor dies 711 of the first stack 701 and a path connecting the first semiconductor die 200 to the third semiconductor dies (712 of FIG. 1) of the second stack (702 of FIG. 1). For example, path differences in terms of length are reduced or eliminated between corresponding paths, one of which connects the first semiconductor die 200 to the second semiconductor dies 711 of the first stack 701 and the other of which connects the first semiconductor die 200 to the third semiconductor dies 712 of the second stack 702. The path connecting the first semiconductor die 200 to the second semiconductor dies 711 may be provided to have substantially the same length as the path connecting the first semiconductor die 200 to the third semiconductor dies (712 of FIG. 1) of the second stack (702 of FIG. 1). Thus, the first semiconductor die 200 may access the second semiconductor dies 711 and the third semiconductor dies 712 with substantially the same signal routing length or a similar signal routing length, thereby improving a signal integrity of the stack package 10.

FIG. 4 is a plan view illustrating the first and second wire bond fingers 140 and 170, the first and second connection bumps 601 and 602, and the first and second die pads 210 and 220 of the stack package 10 shown in FIG. 1. FIG. 5 is an enlarged plan view illustrating the first and second die pads 210 and 220 of the first semiconductor die 200 shown in FIG. 4. FIG. 6 is a plan view focusing on the first connection bumps 601 and the first die pads 210 of FIG. 4.

Referring to FIGS. 1 and 4, the first semiconductor die 200 may have a relatively small size as compared with the second semiconductor dies 711 and the third semiconductor dies 712. In order that the first semiconductor die 200 having a relatively small size is disposed below the first stack 701 including the second semiconductor dies 711, the first semiconductor die 200 may be provided to be embedded in the fan-out sub-package 500. The first wire bond fingers 140 may be arrayed in a column on a first portion of the package substrate 100 where the fan-out sub-package 500 is mounted. The second wire bond fingers 170 may be arrayed in a column on a second portion of the package substrate 100 opposite to the first portion on which the first wire bond fingers 140 are arrayed. The column in which the first wire bond fingers 140 are arrayed and the column in which the second wire bond fingers 170 are arrayed may be substantially symmetric with respect to the first semiconductor die 200 in a plan view.

The fan-out sub-package 500 may be mounted on the package substrate 100 using the first and second connection bumps 601 and 602. The first and second connection bumps 601 and 602 may be disposed between the package substrate 100 and the inner encapsulating layer 300 of the fan-out sub-package 500. The first connection bumps 601 and the second connection bumps 602 may be disposed to be symmetric with respect to the first semiconductor die 200 located between the first connection bumps 601 and the second connection bumps 602 when viewed from a plan view.

The first RDL patterns 401 connecting the first connection bumps 601 to the first die pads 210 of the first semiconductor die 200 may be disposed in the fan-out sub-package 500. The second RDL patterns 402 connecting the second connection bumps 602 to the second die pads 220 of the first semiconductor die 200 may be disposed in the fan-out sub-package 500.

The first interconnection lines 160 connecting the first wire bond fingers 140 to the first connection bumps 601 may be disposed on the package substrate 100. The second interconnection lines 190 connecting the second wire bond fingers 170 to the second connection bumps 602 may be disposed on the package substrate 100.

In general, input/output (I/O) terminals of a semiconductor die may be disposed on a surface of an activation layer in which discrete devices (e.g., MOS transistors) are formed. If the I/O terminals are formed on the surface 201 of the first semiconductor die 200, the number of the I/O terminals which are capable of being disposed on the surface 201 of the first semiconductor die 200 may be limited according to a limited planar area of the surface 201 of the first semiconductor die 200. In order that the first semiconductor die 200 functions as a controller controlling operations of the second and third semiconductor dies 711 and 712, the first semiconductor die 200 has to be electrically connected to the second and third semiconductor dies 711 and 712.

Referring to FIGS. 1, 4, and 5, notwithstanding that the first semiconductor die 200 has a limited area of the surface 201 on which I/O terminals are disposed, it may be necessary to increase the number of the I/O terminals of the first semiconductor die 200 to electrically connect the first semiconductor die 200 to the second and third semiconductor dies 711 and 712. According to an embodiment, a first path connecting the first semiconductor die 200 to the second semiconductor dies 711 and a second path connecting the first semiconductor die 200 to the third semiconductor dies 712 may be independently provided to constitute a plurality of channels. Alternatively, the second semiconductor dies 711 may be signally connected to the first semiconductor die 200 through at least two channels, and the third semiconductor dies 712 may be signally connected to the first semiconductor die 200 through at least two channels. As such, if a plurality of channels are established between the first semiconductor die 200 and the second and third semiconductor dies 711 and 712, the number of the I/O terminals of the first semiconductor die 200 may significantly increase.

As the number of the I/O terminals necessary for the first semiconductor die 200 increases, the number of the first and second die pads 210 and 220 corresponding to the I/O terminals may also increase. Meanwhile, as improved fabrication techniques of semiconductor devices are developed, semiconductor devices can be fabricated to be smaller with the same functionality or even more complicated functionality. In such a case, as a size of the first semiconductor die 200 is reduced, a planar area of the surface 201 of the first semiconductor die 200 may also be reduced. In order to increase the number of the first and second die pads 210 and 220 disposed on a limited area, the first and second die pads 210 and 220 may be disposed to have a loop shape along four edges of the first semiconductor die 200. In an embodiment, the first and second die pads 210 and 220 or some of the first and second die pads 210 and 220 may be arrayed in at least two columns along edges of the first semiconductor die 200. Some of the first and second die pads 210 and 220 may be arrayed in two columns along edges of the first semiconductor die 200 in a zigzag fashion.

In an embodiment, the first semiconductor die 200 may have two opposed edges, for example, a first edge 291 and a second edge 292. In such a case, a first group of the first die pads 210-1 may be arrayed in a first column on an edge region adjacent to the first edge 291 of the first semiconductor die 200. A second group of the first die pads 210-2 may be arrayed in a second column adjacent to the first column located opposite to the first edge 291. In addition, a first group of the second die pads 220-1 may be arrayed in a third column on an edge region adjacent to the second edge 292 of the first semiconductor die 200. A second group of the second die pads 220-2 may be arrayed in a fourth column adjacent to the third column located opposite to the second edge 292. The first semiconductor die 200 may further include two additional opposed edges, for example, a third edge 293 and a fourth edge 294 connecting the first edge 291 to the second edge 292. In such a case, additional die pads of the first die pads 210-3 and additional die pads of the second die pads 220-3 may be arrayed on edge regions adjacent to the third and fourth edges 293 and 294. The additional die pads of the first die pads 210-3 and the additional die pads of the second die pads 220-3 are not arrayed in the first to fourth columns but arrayed along the third and fourth edges 293 and 294 to constitute a loop shape together with the first and second groups of the first die pads 210-1 and 210-2 as well as the first and second groups of the second die pads 220-1 and 220-2.

As described above, some of the first and second die pads 210 and 220 may be arrayed in two columns along the first and second edges 291 and 292, and the remaining ones of the first and second die pads 210 and 220 may be arrayed along the third and fourth edges 293 and 294. Accordingly, the first and second die pads 210 and 220 may be arrayed to have a loop shape or a ring shape in a plan view. Thus, even though a size of the first semiconductor die 200 is reduced, the first semiconductor die 200 may be fabricated without reducing the number of the I/O terminals. As a result, even though the first semiconductor die 200 is signally connected to the second and third semiconductor dies 711 and 712 through a plurality of channels, it may be possible to array the corresponding number of I/O terminals. In the event that the architecture of a multi-chip package, such as the stack package 10, is realized to have a plurality of channels, the performance of the multi-chip package having the multi-channel architecture may be improved as compared with the multi-chip package having a single-channel architecture.

Referring to FIGS. 4, 5, and 6, the first die pads 210 may be electrically connected to the first connection bumps 601 through the first RDL patterns 401. The second die pads 220 may be electrically connected to the second connection bumps 602 through the second RDL patterns 402. A size D1 (i.e., a width) of the first and second die pads 210 and 220 of the first semiconductor die 200 may be less than a diameter D2 of the first and second connection bumps 601 and 602. As described above, because the first semiconductor die 200 requires many I/O terminals in spite of a reduction in the size of the first semiconductor die 200, it may be difficult to increase a size of the first and second die pads 210 and 220. Meanwhile, in order to mount the fan-out sub-package 500 on the package substrate 100, it may be necessary to stably maintain the electrical connections in the stack package 10 even though the package substrate 100 and the fan-out sub-package 500 are deformed during a package process of the stack package 10. Thus, a size of the first and second connection bumps 601 and 602 should be greater than a certain value. For example, the first and second die pads 210 and 220 may be formed to have the size D1 (i.e., a width) of approximately a few micrometers to approximately several tens of micrometers, and the first and second connection bumps 601 and 602 may be formed to have the diameter D2 of approximately several tens of micrometers to approximately several hundreds of micrometers. Because the size D1 of the first and second die pads 210 and 220 is relatively small, it may be difficult to directly connect the first and second die pads 210 and 220 to the first and second connection bumps 601 and 602 having the diameter D2 of a relatively large value. Thus, the first and second connection bumps 601 and 602 may be connected to the first and second die pads 210 and 220 through the first and second RDL patterns 401 and 402.

The first connection bumps 601 may be disposed along an edge of the fan-out sub-package 500, which is adjacent to the first wire bond fingers 140, to correspond with respective first die pads 210. When the first die pads 210 are arrayed in two columns, the first connection bumps 601 may also be arrayed in two columns to correspond with respective first die pads 210. The first connection bumps 601 may include a first group of the first connection bumps 601-1 and a second group of the first connection bumps 601-2. The first group of the first connection bumps 601-1 may be arrayed in a first column adjacent to an edge of the fan-out sub-package 500, and the second group of the first connection bumps 601-2 may be arrayed in a second column between the first column and the first semiconductor die 200. The first connection bumps 601 may be arrayed in two columns in a zigzag fashion. Thus, it may be possible to maximize space between the first group of the first connection bumps 601-1 and the second group of the first connection bumps 601-2. The second connection bumps 602 may also be arrayed in two columns to correspond with respective second die pads 220 which are arrayed in two columns. The second connection bumps 602 may be arrayed in two columns in a zigzag fashion. The second connection bumps 602 may include a first group of the second connection bumps 602-1 and a second group of the second connection bumps 602-2 like the first connection bumps 601.

Referring again to FIGS. 4, 5, and 6, the first connection bumps 601 may be disposed to have a second pitch W2 which is greater than a first pitch W1 of the first die pads 210. The first wire bond fingers 140 may be disposed to have a third pitch W3 which is less than the second pitch W2 of the first connection bumps 601. A first sub-wire bond finger 141 and a second sub-wire bond finger 142, which are disposed to be immediately adjacent to each other, among the first wire bond fingers 140 may be disposed to have the third pitch W3. A distance between the first sub-wire bond finger 141 and the second sub-wire bond finger 142 may be smallest among distances between the first wire bond fingers 140. Thus, the third pitch W3 may mean a minimum pitch among the pitches of the first wire bond fingers 140.

In order that the first die pads 210 are disposed to have the first pitch in a limited area, the first die pads 210 may be arrayed in two columns. The first pitch W1 of the first die pads 210 arrayed in two columns may be greater than a pitch of the first die pads 210 when the first die pads 210 are arrayed in one column. Thus, when the first RDL patterns 401 connected to the first die pads 210 are formed, it may be possible to increase or maximize distances between the first RDL patterns 401.

The first wire bond fingers 140 may be disposed to have the third pitch W3 which is greater than the first pitch W1 of the first die pads 210. Because the first wire bond fingers 140 are formed to have a scale which is different from a scale of the first die pads 210, it may be difficult to directly connect the first wire bond fingers 140 to the first die pads 210. Thus, an interconnection structure may be used to electrically connect the first wire bond fingers 140 to the first die pads 210. The first RDL patterns 401, the first connection bumps 601 and the first interconnection lines 160 may be used to electrically connect the first wire bond fingers 140 to the first die pads 210.

Referring to FIGS. 1 and 4, the first connection bumps 601 may be bonded to the first bump bond fingers 150 by a soldering process of the conductive adhesive layers 612. In such a case, in order to prevent the first connection bumps 601 adjacent to each other from being undesirably connected to each other due to a poor soldering process, the first connection bumps 601 may be disposed to have the second pitch W2 which is greater than the third pitch W3 of the first wire bond fingers 140. In order that the first connection bumps 601 are disposed to have the second pitch W2 corresponding to a relatively large pitch, the first group of the first connection bumps 601-1 and the second group of the first connection bumps 601-2 may be arrayed in two columns in a zigzag fashion.

Referring again to FIG. 1, the fan-out sub-package 500 may have a size which is greater than a size of the second bottommost semiconductor die 711B, which is included in the first stack 701. In an embodiment, the fan-out sub-package 500 may have substantially the same size as the second bottommost semiconductor die 711B. The second bottommost semiconductor die 711B may correspond to the second semiconductor die 711, which is closest to the fan-out sub-package 500 among the second semiconductor dies 711 of the first stack 701. Because the fan-out sub-package 500 has the same size as the second bottommost semiconductor die 711B or has a size which is greater than a size of the second bottommost semiconductor die 711B, the second bottommost semiconductor die 711B may be disposed on the fan-out sub-package 500 without any overhang. Thus, the second bottommost semiconductor die 711B may be disposed to fully overlap with the fan-out sub-package 500. In addition, because the remaining second semiconductor dies 711 stacked on the second bottommost semiconductor die 711B can be disposed without any overhang, it may be possible to form a stable stack structure on the fan-out sub-package 500.

FIG. 7 is an enlarged cross-sectional view illustrating an edge portion 500E of the fan-out sub-package 500 included in the stack package 10 according to an embodiment.

Referring to FIG. 7, the fan-out sub-package 500 may be disposed on the package substrate 100 to have a protrusion 500P extending beyond a side surface of the first stack 701 including the second semiconductor dies 711 when viewed from a plan view. The protrusion 500P of the fan-out sub-package 500 may extend beyond a side surface of the second bottommost semiconductor die 711B, which is included in the first stack 701, in a plan view. The second bottommost semiconductor die 711B may be disposed on the fan-out sub-package 500 such that a portion of the edge portion 500E of the fan-out sub-package 500 extends beyond a side surface of the second bottommost semiconductor die 711B when viewed from a plan view.

The first group of the first connection bumps 601-1 among the first connection bumps 601 may be vertically overlapped by the protrusion 500P of the fan-out sub-package 500. Thus, the first group of the first connection bumps 601-1 may stably support the protrusion 500P of the fan-out sub-package 500.

The second group of the first connection bumps 601-2 among the first connection bumps 601 may be vertically overlapped by connection portions 811A where the first bonding wires 801 are connected to the second bottommost semiconductor die 711B closest to the fan-out sub-package 500 among the second semiconductor dies 711.

The second group of the first connection bumps 601-2 may be vertically overlapped by an edge portion 711E of the second bottommost semiconductor die 711B. The connection portions 811A corresponding to first ends of the first sub-bonding wires 811 may be bonded to the edge portion 711E of the second bottommost semiconductor die 711B. The second group of the first connection bumps 601-2 may be partially or fully overlapped by the connection portions 811A of the first bonding wires 801. Thus, when the first bonding wires 801 are bonded to the second bottommost semiconductor die 711B, the second group of the first connection bumps 601-2 may support the edge portion 711E of the second bottommost semiconductor die 711B such that the fan-out sub-package 500 and the second bottommost semiconductor die 711B are not damaged by the bonding pressure. Accordingly, the first bonding wires 801 may be more stably bonded to the second bottommost semiconductor die 711B.

So that the second group of the first connection bumps 601-2 are overlapped by the connection portions 811A of the first bonding wires 801, the edge portion 500E of the fan-out sub-package 500 may extend to be overlapped by the connection portions 811A of the first bonding wires 801.

FIG. 8 is a cross-sectional view illustrating a stack package 11 according to another embodiment. In FIG. 8, the same reference numerals as used in FIG. 1 denote the same elements.

Referring to FIG. 8, the stack package 11 may include the package substrate 100, the fan-out sub-package 500 including the first semiconductor die 200, the first stack 701 comprised of the second semiconductor dies 711, the second stack 702 comprised of the third semiconductor dies 712, the first and second bonding wires 801 and 802, the first and second connection bumps 601 and 602, and the outer encapsulating layer 900. The second semiconductor dies 711 may be stacked on the fan-out sub-package 500 to provide the first step structure 701S, and the third semiconductor dies 712 may be stacked on the first stack 701 to provide the second step structure 702S. The first and second RDL patterns 401 and 402 may be disposed in the fan-out sub-package 500.

First dummy bumps 604 may be disposed between a position where the first connection bumps 601 are disposed and a position where the second connection bumps 602 are disposed. The first dummy bumps 604 may include at least two bumps to structurally support the fan-out sub-package 500. The first dummy bumps 604 may be disposed on the dielectric layer 350. Because the first dummy bumps 604 are disposed on the dielectric layer 350, the first and second RDL patterns 401 and 402 may be electrically insulated and isolated from the first dummy bumps 604 by the dielectric layer 350. The package substrate 100 may further include first dummy fingers 120 to which the first dummy bumps 604 are bonded. The first dummy fingers 120 may be conductive patterns like the first wire bond fingers 140. The first dummy bumps 604 may be formed to have substantially the same shape as the first connection bumps 601 or to have a similar shape to the first connection bumps 601.

The first dummy bumps 604 may be vertically overlapped by the inner encapsulating layer 300 of the fan-out sub-package 500 and may be spaced apart from the first semiconductor die 200 in a horizontal direction. The first dummy bumps 604 may be disposed to be adjacent to the first and second connection bumps 601 and 602. For example, some of the first dummy bumps 604 may be disposed to be adjacent to the second group of the first connection bumps 601-2. The first dummy bumps 604 disposed as described above may additionally support the second semiconductor dies 711 when the first bonding wires 801 are bonded to the second semiconductor dies 711. Accordingly, it may be possible to prevent the fan-out sub-package 500 from being damaged or the second semiconductor dies 711 from being bent by bonding pressure. As a result, it may be possible to effectively lower or suppress the occurrence of bonding failure.

FIG. 9 is a cross-sectional view illustrating a stack package 12 according to yet another embodiment. In FIG. 9, the same reference numerals as used in FIG. 1 denote the same elements.

Referring to FIG. 9, the stack package 12 may include the package substrate 100, the fan-out sub-package 500 including the first semiconductor die 200, the first stack 701 comprised of the second semiconductor dies 711, the second stack 702 comprised of the third semiconductor dies 712, the first and second bonding wires 801 and 802, the first and second connection bumps 601 and 602, and the outer encapsulating layer 900.

Second dummy bumps 605 may be disposed between a position where the first connection bumps 601 are disposed and a position where the second connection bumps 602 are disposed. The second dummy bumps 605 may be overlapped by the first semiconductor die 200 corresponding to a central portion of the fan-out sub-package 500. The second dummy bumps 605 may include at least two bumps to support the fan-out sub-package 500. The second dummy bumps 605 may be disposed on the dielectric layer 350. The package substrate 100 may further include second dummy fingers 130 to which the second dummy bumps 605 are bonded.

The second dummy bumps 605 may function as supporters for structurally supporting the fan-out sub-package 500. The second dummy bumps 605 may decentralize the load applied to the fan-out sub-package 500. The second dummy bumps 605 may act as distributors for dispersing pressure locally applied to the fan-out sub-package 500 during a wire bonding process in which the first bonding wires 801 are bonded to the second semiconductor dies 711.

The first dummy bumps 604 illustrated in FIG. 8 may be provided to include at least two bumps and may be disposed between a position where the first connection bumps 601 are disposed and a position where the second connection bumps 602 are disposed. Similarly, the second dummy bumps 605 illustrated in FIG. 9 may also be provided to include at least two bumps and may be disposed between a position where the first connection bumps 601 are disposed and a position where the second connection bumps 602 are disposed. The first and second dummy bumps 604 and 605 may induce the outer encapsulating layer 900 to more readily fill a space between the fan-out sub-package 500 and the package substrate 100. During a molding process for forming the outer encapsulating layer 900, a molding material may fill the space between the fan-out sub-package 500 and the package substrate 100. The first and second dummy bumps 604 and 605 may disperse the molding material to induce uniform flow of the molding material during the molding process. Accordingly, the first and second dummy bumps 604 and 605 may prevent, suppress, or mitigate the generation of voids in the space between the fan-out sub-package 500 and the package substrate 100 when the molding process is performed.

In an embodiment, the space between the fan-out sub-package 500 and the package substrate 100 may be filled with an underfill material. In such a case, the first and second dummy bumps 604 and 605 may improve a flowability of the underfill material to prevent voids from being formed in the space between the fan-out sub-package 500 and the package substrate 100.

FIG. 10 is a block diagram illustrating an electronic system including a memory card 7800 employing at least one stack package according to an embodiment. The memory card 7800 includes a memory 7810, such as a nonvolatile memory device, and a memory controller 7820. The memory 7810 and the memory controller 7820 may store data and/or read out stored data. At least one of the memory 7810 and the memory controller 7820 may include at least one stack package according to an embodiment.

The memory 7810 may include a nonvolatile memory device to which the teachings of the present disclosure can be applied. The memory controller 7820 may control the memory 7810 such that stored data is read out or data is stored in response to a read or write request from a host 7830.

FIG. 11 is a block diagram illustrating an electronic system 8710 including at least one stack package according to an embodiment. The electronic system 8710 may include a controller 8711, an input/output unit 8712, and a memory 8713. The controller 8711, the input/output unit 8712, and the memory 8713 may be coupled with one another through a bus 8715 providing a path through which data moves.

In an embodiment, the controller 8711 may include one or more microprocessor, digital signal processor, microcontroller, and/or logic device capable of performing the same functions as these components. The controller 8711 and/or the memory 8713 may include at least one stack package according to an embodiment of the present disclosure. The input/output unit 8712 may include at least one selected from among a keypad, a keyboard, a display device, a touchscreen, and so forth. The memory 8713 is a device for storing data. The memory 8713 may store data and/or commands to be executed by the controller 8711, and the like.

The memory 8713 may include a volatile memory device, such as a DRAM, and/or a nonvolatile memory device such as a flash memory. For example, a flash memory may be mounted to an information processing system such as a mobile terminal or a desktop computer. The flash memory may constitute a solid state disk (SSD). In this case, the electronic system 8710 may stably store a large amount of data in a flash memory system.

The electronic system 8710 may further include an interface 8714 configured to transmit and receive data to and from a communication network. The interface 8714 may be of a wired or wireless type. For example, the interface 8714 may include an antenna or a wired or wireless transceiver.

The electronic system 8710 may be realized as a mobile system, a personal computer, an industrial computer, or a logic system performing various functions. For example, the mobile system may be any one of a personal digital assistant (PDA), a portable computer, a tablet computer, a mobile phone, a smart phone, a wireless phone, a laptop computer, a memory card, a digital music system, and an information transmission/reception system.

If the electronic system 8710 represents equipment capable of performing wireless communication, the electronic system 8710 may be used in a communication system using a protocol of CDMA (code division multiple access), GSM (global system for mobile communications), NADC (north American digital cellular), E-TDMA (enhanced-time division multiple access), WCDMA (wideband code division multiple access), CDMA2000, LTE (long term evolution), or Wibro (wireless broadband Internet).

A limited number of possible embodiments for the present disclosure have been presented for illustrative purposes. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the present disclosure and the accompanying claims. 

What is claimed is:
 1. A stack package comprising: a package substrate; a fan-out sub-package mounted on the package substrate using first connection bumps and second connection bumps; a first stack of second semiconductor dies stacked on the fan-out sub-package; a second stack of third semiconductor dies stacked on the second semiconductor dies; first bonding wires connected to the second semiconductor dies; and second bonding wires connected to the third semiconductor dies, wherein the package substrate comprises: first wire bond fingers connected to the first bonding wires; second wire bond fingers connected to the second bonding wires; first bump bond fingers to which the first connection bumps are connected; and second bump bond fingers to which the second connection bumps are connected, and wherein the fan-out sub-package comprises: an encapsulating layer embedding a first semiconductor die; first redistributed line (RDL) patterns extending from a surface of the first semiconductor die and connecting to the first connection bumps disposed on a bottom surface of the encapsulating layer; and second RDL patterns extending from the surface of the first semiconductor die and connecting the first semiconductor die to the second connection bumps disposed on the bottom surface of the encapsulating layer.
 2. The stack package of claim 1, wherein the second semiconductor dies are stacked with an offset in a first offset direction directed from the first wire bond fingers toward the second wire bond fingers to provide a first step structure; and wherein the third semiconductor dies are stacked with an offset in a second offset direction directed from the second wire bond fingers toward the first wire bond fingers to provide a second step structure.
 3. The stack package of claim 1, wherein: the first wire bond fingers are located on a first side of the fan-out sub-package; and the second wire bond fingers are located on a second side of the fan-out sub-package opposite to the first side of the fan-out sub-package.
 4. The stack package of claim 1, wherein the first semiconductor die is disposed above a central portion of the package substrate located between the first wire bond fingers and the second wire bond fingers.
 5. The stack package of claim 1, wherein the first and second connection bumps are laterally spaced apart from the first semiconductor die.
 6. The stack package of claim 1, wherein the package substrate further comprises: first interconnection lines respectively connecting the first wire bond fingers to the first bump bond fingers; and second interconnection lines respectively connecting the second wire bond fingers to the second bump bond fingers.
 7. The stack package of claim 6, wherein the first semiconductor die comprises: first die pads respectively and electrically connected to the first RDL patterns; and second die pads respectively and electrically connected to the second RDL patterns, wherein the first and second die pads have a width which is less than a diameter of the first and second connection bumps.
 8. The stack package of claim 7, wherein: the first die pads, the first RDL patterns, the first connection bumps, the first bump bond fingers, the first interconnection lines, and the first wire bond fingers form first electrical paths; and the second die pads, the second RDL patterns, the second connection bumps, the second bump bond fingers, the second interconnection lines, and the second wire bond fingers form second electrical paths.
 9. The stack package of claim 8, wherein the first electrical paths have the same lengths as the second electrical paths, respectively.
 10. The stack package of claim 7, wherein the first die pads are arrayed in two columns along edges of the first semiconductor die in a zigzag fashion.
 11. The stack package of claim 10, wherein the first connection bumps are arrayed in two columns in a zigzag fashion to correspond to the first die pads arrayed in two columns in a zigzag fashion.
 12. The stack package of claim 7, wherein the first connection bumps as arrayed have a pitch which is greater than a pitch of the first die pads as arrayed.
 13. The stack package of claim 12, wherein the first wire bond fingers as arrayed have a pitch which is less than the pitch of the first connection bumps as arrayed.
 14. The stack package of claim 7, wherein the first and second die pads are disposed along edges of the first semiconductor die in a loop-shaped arrangement.
 15. The stack package of claim 7, wherein: the first and second die pads are located on a body surface of the first semiconductor die; the locations of the first die pads are point symmetric with the locations of the second die pads with respect to a central point on the body surface of the first semiconductor die; the locations of the first connection bumps are symmetric with the locations of the second connection bumps with respect to the first semiconductor die; and the locations of the first wire bond fingers are symmetric with the locations of the second wire bond fingers with respect to the first semiconductor die.
 16. The stack package of claim 1, wherein a size of the first semiconductor die is less than a size of the second semiconductor dies.
 17. The stack package of claim 1, wherein a size of the fan-out sub-package is substantially equal to or greater than a size of a second bottommost semiconductor die which is stacked to be closest to the fan-out sub-package among the second semiconductor dies.
 18. The stack package of claim 17, wherein the second bottommost semiconductor die is disposed to fully overlap the fan-out sub-package.
 19. The stack package of claim 1, wherein the fan-out sub-package has a protrusion extending beyond a side surface of the first stack.
 20. A stack package comprising: a package substrate; a fan-out sub-package mounted on the package substrate using first connection bumps and second connection bumps; second semiconductor dies stacked on the fan-out sub-package to provide a step structure; bonding wires connecting the second semiconductor dies to the package substrate; and dummy bumps disposed between the first connection bumps and the second connection bumps to structurally support the fan-out sub-package, wherein the fan-out sub-package comprises: an encapsulating layer embedding a first semiconductor die; first redistributed line (RDL) patterns extending from a surface of the first semiconductor die and connecting to the first connection bumps disposed on a bottom surface of the encapsulating layer; and second RDL patterns extending from the surface of the first semiconductor die and connecting the first semiconductor die to the second connection bumps disposed on the bottom surface of the encapsulating layer. 